Case Studies

Thysanothecium

The genus Thysanothecium was first described in 1846 in a paper by Jean Pierre François Camille Montagne and the Reverend Miles Joseph Berkeley. It was the first description of a lichen genus based on Australian material and the authors start their paper with the following paragraph:

The remarkable production here characterised formed part of an extensive collection of Swan River Cryptogams sent to Sir W.J. Hooker by Mr. Drummond. The older individuals, though their affinity to the great division of Lichens is very evident, bear a striking resemblance to Cantharellus undulatus, Fr. Unfortunately no sporidia have been detected; the series of specimens is, however, too perfect to allow of the supposition that it is merely a strange form of some well known genus.

The story started several years earlier. In an 1843 letter from James Drummond to William Hooker, the former described one of his collections, number 69, as a "curious species with spathulate shields of a white or brown colour found on white anthills". A parcel of specimens, including this "curious species", reached the botanic gardens at Kew in 1844 and Hooker, who initially thought it to be a fungus, passed some material on to Berkeley, to whom Hooker frequently referred fungal questions. Some time later Berkeley sent it to Montagne in Paris. In a letter to Berkeley in January 1845 Montagne wrote that the "plant is very curious and I think it is a new genus in the family of lichens...I propose the name Schistothecium on account of the laciniate proligerous area". The 'schisto' part of that proposed name denotes split or divided. Though Montagne was convinced that this was a new genus, with the thallus showing some resemblance to that of a Ramalina, he was disappointed to find no spores.

Joseph Hooker (son of William) visited Paris in February 1845 and, at Berkeley's request, Montagne showed him the lichen. He was as intrigued by it as Berkeley and Montagne had been and wrote to Berkeley:

...It is indeed extraordinary, but Lichens are so protean that you will excuse my supposing what may truly be a preposterous supposition, that it is a form of Ramalina, in other words may it not represent a branch, with a distorted apothecium (N.B. barren and turned away from the light). Montagne is so positive of its novelty that I dare hardly hint this to him, and he knows so much more of these things than I do as makes me fear committing myself. The whole thing looks unnatural to me, and now that so many diseased states of the lower orders have been made into genera I should be cautious; my procedure with a barren plant. Indeed no lichen should be described without a large series of specimens.

A little later Montagne wrote to Berkeley to say that the name Schistothecium was already in use and Berkeley suggested Dochmiothecium. Joseph Hooker, on his return to England, re-examined the material still at Kew and sent some additional specimens to Berkeley, who then thought there could be a second species involved. After his examination of the additional specimens Berkeley wrote to Hooker at the end of May:

...I was very much pleased to see among Drummond's things a second species of the supposed Lichen genus. I have not been able to find asci and sporidia in it. I am really inclined to think it must be distinct.

Thomas Taylor in Ireland, a long-time correspondent of the Hookers', was another who received lichens from Drummond. While Berkeley and Montagne were exchanging letters, Joseph Hooker was corresponding with Taylor about the identification of the lichens Hooker had collected in the Southern Hemisphere during the James Clerk Ross expedition of 1839-1843. In an undated 1845 letter to Berkeley Joseph Hooker wrote of his joint work with Taylor and that, for the puzzling Drummond lichen, he had suggested the genus name Ripidior (meaning 'fan') to Taylor but that "...the second species may alter the name or you may have a better for them both". In the years since European settlement in Australia the country had provided many examples of what, to European eyes, seemed biological oddities. In the same letter Hooker noted that this lichen was "...an Australian anomaly and the first example of this custom Australia has of producing anomalies being extended to Lichens". In a reply Berkeley pointed out a problem with the name Ripidior and also asked what Hooker wished to do as far as publication was concerned, in particular "...if you and Dr. Taylor would like to publish it I had better send you the second species". Hooker however had much to do (in particular his work on the specimens collected during the Ross expedition), was quite happy to have Berkeley publish the new genus and was sure that Taylor would be of the same mind. Therefore Hooker now offered Berkeley the material still left at Kew since "...they may be better than yours, they have good crust and brown purple apothecia, in the latter I expected to find asci but am quite disappointed...I enclose a few coloured apothecia lest you have them not".

Montagne had considered the name Dochmiothecium but declined it in favour of another name of his own devising - Thysanothecium. The 'thysano' root denotes fringed or tasselled. At the end of April 1845 Montagne wrote to Berkeley that "...the name Dochmiothecium is good but it is not very euphonic; would you not prefer Thysanothecium which is not a syllable longer and which has the same meaning...". In a letter of May 22 Montagne sent Berkeley the formal description of the new genus and again stressed the more euphonious sound of Thysanothecium, noting that was "...also the sentiment of Durieu, Webb and Roussel whom I have consulted".

On 10 June 1845 Taylor wrote to Joseph Hooker:

...I shall, likewise, be obliged by your informing me in what publication Mr. Berkeley has described the new genus of Lichen from Swan River for I believe I have a specimen of it from James Drummond, and have made MSS generic characters. I am, therefore, most curious to see Mr. Berkeley's different mode of 'envisagement' of the same subject, and so to correct my own notions.

However, at that time the new genus was still far from publication. Joseph Hooker was to produce the drawings to go with the text, but he was unable to do so until his return from Edinburgh where he had gone to deliver a series of botanical lectures at the city's university, seemingly with the aim of succeeding to a professorship there. Thus it was not until 1846 that the description of the new genus (with the one species Thysanothecium hookeri) was published, with some modifications to Montagne's description by Berkeley.

In 1847 Taylor published a description of the new species Baeomyces hyalinus based on some Drummond specimens from Western Australia. Taylor published no comments as to any similarity between his species of Baeomyces and the genus Thysanothecium but in 1857 William Nylander realized that this species belonged in the genus Thysanothecium and so it became known as Thysanothecium hyalinum.

Amongst the lichens collected in Western Australia by Ludwig Preiss around 1840 was a new species named as Cladonia scutellata by Elias Fries, though he had some doubts as to its place in the genus Cladonia. The information about the Preiss lichen collections was published in 1846 as part of volume 2 of Plantae Preissiana, under the editorship of Christian Lehmann. Later research has shown that Fries' species belongs in the genus Thysanothecium and, since 1982, has been known by the name Thysanothecium scutellatum. Moreover, Taylor's species has been shown to be identical to the species of Fries which, as the earlier published, gives priority to the scutellatum epithet.

As noted earlier Berkeley had suspected there to be two species present in the Drummond material he'd seen but in their joint paper Montagne and Berkeley published a description of just the one species. They cited two Drummond collections, numbers 69 and 70 and took these collections to be a mixture of young and old specimens of the same species. In their paper Montagne and Berkeley noted that Thysanothecium hookeri grew on charred wood or on bare soil. The surviving specimens of collection number 70 are on charred wood, whereas all the other Drummond collections of Thysanothecium are from termite nests. Drummond's collections 69 and 70 do in fact represent Thysanothecium hookeri and Thysanothecium scutellatum. Joseph Hooker's drawings clearly showed both species, without his realizing so. Here are two of Hooker's drawings, courtesy of the Missouri Botanical Garden (http://www.botanicus.org):

The "young plants" on the left are shown clearly on a piece of charred wood, while the "full grown plants" on the right are on a pale substrate, the "white anthills" as noted originally by Drummond.

For many years Thysanothecium hookeri and Thysanothecium scutellatum were the only two species known for the genus. The former can be found on soil, anthills, termite mounds and sandstone boulders and the latter shows a strong preference for charred wood, though it can also be found on decorticated, unburnt wood. The specimens collected by Preiss came from the caudex of a Macrozamia. Thysanothecium hookeri has been found in various parts of Australia and New Zealand but the other species has a much wider distribution. It has been found in Australia, New Zealand, New Caledonia, Papua New Guinea, parts of south-east Asia and Japan. A third species, Thyasnothecium sorediatum, was described in a paper published in 2009 and this species been found in Queensland and New South Wales, mostly on the bases of eucalypt trees at rainforest margins but is also known from charred wood in dry sclerophyll forests. The same paper also presented a description of a new sub-species of Thysanothecium hookeri, found on soil in sub-arid Western Australia.

References

Galloway, DJ. (1977). The lichen genus Thysanothecium Mont. & Berk., an historical note. Nova Hedwigia, 28, 499-513. [ Galloway gives a lengthy history and quotes from various unpublished letters. He gives the extracts from Monatgne's letters in the original French and the translations given above are mine.]